JP6274113B2 - Data transmission apparatus, data transmission method, and program thereof - Google Patents

Description

  The present invention relates to a network technology, and more particularly, to a data transmission apparatus, a data transmission method, and a program for realizing significant traffic control.

  In recent years, with the improvement of Internet line capacity and the development of elemental technologies for handling various media information, it has become possible to enjoy rich media information distribution anytime, anywhere from mobile terminals. Such lifestyles have become widespread, and communication environments such as LTE (Long Term Evolution) are spreading and expanding as high-speed mobile environments that support information distribution.

  In the high-speed mobile communication environment such as LTE, various technologies for improving the efficiency of data communication are introduced in the protocols of each layer. For example, in the RLC (Radio Link Control) layer of LTE, the data passed from the upper layer is divided and linked on the transmission side so that each service data unit can be used up in order to reduce unnecessary fragments and overhead. On the receiving side, processing is performed such that the order is controlled and restored, and the data is passed to the upper layer.

  In addition, in a MAC (Media Access Control) layer in LTE or HSDPA (High Speed Downlink Packet Access), data is made redundant in advance in a wireless network in which bit errors are likely to occur. HARQ (Hybrid Automatic Repeat reQuest) technology that efficiently corrects communication data errors by retransmitting 8 by 8 has been introduced. According to this HARQ technique, data retransmission and repair processing can be completed below the MAC layer, and the amount of data to be retransmitted can be reduced, so that effective use of the radio band can be realized.

According to the data division / concatenation processing and HARQ technology in the high-speed mobile communication environment described above, it is possible to virtually provide a network with less overhead and errors as viewed from the upper layer protocol (in conjunction with the upper layer). Error seen from the layer protocol).
However, since the technical content is that the bit error is recovered by retransmission, there is an inconvenience that a delay occurs when viewed from the upper layer protocol.

  In addition, TCP (Transmission Control Protocol), which has been widely used for both wired and wireless data communication since ancient times, has advanced technology for congestion control to cope with the recent communication environment in which a lot of traffic coexists. It has become.

  In this regard, in delay-based TCP represented by TCP Vegas (Non-Patent Document 1) and FAST TCP (Non-Patent Document 2), packets are detected by detecting congestion by analyzing an increase in delay. The data transmission rate can be suppressed before a loss occurs, and thus it is possible to avoid the network failure and stabilize the throughput.

  However, in the delay-based TCP disclosed in each of the above non-patent documents 1 and 2, when the product of the available bandwidth and the delay increase amount exceeds a set threshold value, it is determined that there is a congestion state and data is transmitted. Since control for reducing the rate is performed, even when the increase in delay is not caused by congestion, it is erroneously recognized that congestion has occurred, and there is a disadvantage that the transmission rate is unnecessarily reduced.

  As related techniques made in view of such problems, for example, the following technical contents (Patent Document 1 or 2) are known.

  In Patent Document 1, when a burst-like packet loss occurs during streaming, a link failure (failure such as disconnection of a communication link due to disconnection of an optical fiber) or a node failure (failure of a device such as a router or a router configuration) The technical content is disclosed that the stream transmission rate is maintained by determining that the failure is caused by an abnormality in the network) and using the saved past network statistical information instead of the current one.

  In Patent Document 2, it is determined whether or not there is a congestion state by analyzing the feedback data and whether or not there is a transmission error. The technical content is disclosed that the distribution is considered to have not occurred, and the transfer rate is maintained without being changed.

L.S. Brakmo, S. O'Malley, and L.L.Peterson, “TCP Vegas: New Techniques for Congestion Detection and Avoidance,” Computer Communication Review, vol.24, no.4, pp.24-35, Oct. 1994. C. Jin, D. Wei, and S. Low, “FAST TCP: Motivation, Architecture, Algorithms, Performance,” in Proc. Of IEEE INFOCOM, Hong Kong, Mar. 2004.

JP 2006-5775 A JP 2001-160824 A

  However, the technical contents disclosed in Patent Documents 1 and 2 are based on the assumption that easy-to-understand phenomena such as packet loss and transmission error can be observed, and determine whether congestion has occurred using the occurrence rate of these phenomena. For this reason, in a communication environment such as LTE in which transmission errors are repaired in the lower layer and packet loss or the like is difficult to see from the upper layer, there is a disadvantage that the system capable of discriminating congestion deteriorates.

(Object of invention)
The present invention, the prior art related examples are intended to improve the disadvantages possessed by, in particular, the data transmission apparatus also delays increase due to reasons other than congestion in the network occurs to effectively improve the throughput (transmission efficiency) An object of the present invention is to provide a data transmission method and a program thereof.

  To achieve the above object, the data transmission device according to the present invention is a data transmission device including a transmission unit that transmits data to a user terminal, and an increase in delay in data transmission is caused by network congestion. A determination function for determining whether or not the transmission is based on a predetermined criterion, and controlling the operation of the transmission unit so as not to decrease the transmission rate when the determination function determines that it is not caused by congestion And a transmission operation control unit having a transmission rate control function.

  Further, in the data transmission method according to the present invention, in the data transmission device including a transmission unit for transmitting data to the user terminal, whether or not an increase in delay in data transmission is caused by network congestion. Is determined based on a predetermined criterion, and when it is determined that it is not caused by congestion, the detection criterion set in advance is corrected, and the degree of congestion is detected based on the corrected detection criterion, According to the result of this detection, the operation of the transmission unit is controlled so as not to lower the transmission rate.

  Furthermore, in the data transmission program according to the present invention, there is provided a data transmission apparatus including a transmission unit that transmits data to a user terminal, and whether or not an increase in delay for data transmission is caused by network congestion. A delay cause determination function for determining the detection criterion based on a predetermined criterion, a detection reference correction function for correcting a preset detection reference when it is determined that the delay cause determination function is not caused by congestion, and this detection reference correction A congestion detection function that detects the degree of congestion based on the detection criteria corrected by the function, and a transmission rate control that controls the operation of the transmission unit so as not to lower the transmission rate according to the detection result by the congestion detection function The function is realized by a computer.

  According to the present invention, in particular, it is possible to provide a data transmission apparatus, a data transmission method, and a program thereof capable of effectively improving throughput (transmission efficiency) even when a delay increase due to reasons other than congestion occurs in a network. Is possible.

It is a block diagram which shows the structure of the data transmission device concerning 1st Embodiment of this invention, and its surrounding environment. 3 is a flowchart illustrating operations from network delay measurement processing to data transmission rate control by the data transmission device disclosed in FIG. 1. 3 is a flowchart showing operations from network delay measurement processing by the data transmission device disclosed in FIG. 1 to determination regarding the cause of the increase in delay and correction of congestion parameters based on the determination. It is a block diagram which shows the structure of the data transmitter concerning 2nd Embodiment of this invention, and its surrounding environment. FIG. 5 is a flowchart showing operations from network delay measurement processing by the data transmission device disclosed in FIG. 4 to determination regarding the cause of the increase in delay and correction of congestion parameters based on the determination;

[First Embodiment]
A data transmission apparatus according to a first embodiment of the present invention will be described with reference to FIGS.

(Basic configuration)
First, the basic configuration contents of the data transmission apparatus according to the first embodiment and the surrounding environment will be described with reference to FIG.

  As shown in FIG. 1, a data transmission device 11 that performs data transmission in response to a request from the outside is provided connected to a network 20 such as the Internet. Reference numeral 30 denotes a user terminal (request source terminal) that acquires data relating to the request by transmitting a data acquisition request from a user or the like to the data transmission device 11 via the network 20, for example, a PC (Personal Computer) and portable terminals fall under this category. That is, the network 20 functions as a configuration that connects the user terminal 30 and the data transmission device 11.

  As the data transmission device 11, for example, an origin server that holds data requested by a user, a cache server, a proxy server, an edge server, or the like is installed in the network 20 and data between the origin server and the user terminal 30 A relay server device that terminates communication once, or a data communication device that constitutes the network 20 such as a P-GW (Packet Data Network Gateway) or S-GW (Serving Gateway) can be adopted. Also, the requested data is transmitted by establishing a connection such as TCP to the user terminal 30.

  Here, when a relay server device or the like is employed as the data transmission device 11, an origin server may be arranged in the middle of a route for transmitting data to the user terminal 30. For example, another network (not shown) or an origin server (not shown) for holding the requested data may be provided behind the data transmitting apparatus 11.

  That is, when a data acquisition request is made by a user or the like, the user terminal 30 transmits a data request to the data transmission device 11 or the origin server via the network 20, and in response to this, the data transmission device 11 or Data relating to the request is distributed from the origin server to the user terminal 30. The user terminal 30 is configured to present the data to the user or the like when the data is distributed.

  In addition, the data transmission apparatus 11 including the transmission unit 60 that transmits data to the user terminal 30 determines whether or not the increase in delay for data transmission is caused by network congestion based on a predetermined criterion. A transmission operation control unit 51 having a determination function for determining the transmission rate, and a transmission rate control function for controlling the operation of the transmission unit 60 so as not to decrease the transmission rate when the determination function determines that it is not caused by congestion, It has.

  Accordingly, the transmission operation control unit 51 that has determined that the delay has increased due to a cause other than congestion by analyzing the delay or the like related to data transmission controls the operation of the transmission unit 60 by adjusting the transmission rate. Inconvenience that the transmission rate is lowered in the case of an increase in delay due to reasons other than the above can be suppressed, thereby improving the throughput.

(Specific configuration)
Next, the specific configuration contents of the data transmission device according to the first embodiment and the surrounding environment will be described with reference to FIG.

  As shown in FIG. 1, the data transmission device 11 that transmits data requested via the network 20 to the user terminal 30 measures a delay related to packet transmission on the network 20 and measures the measured value (delay). ) Or a delay measurement processing unit 40 for storing and processing the statistical value and the network information subjected to statistical processing in an internal memory or the like (not shown), and an increase in delay stored by the delay measurement processing unit 40 A transmission operation control unit 51 that determines whether or not it is caused by network congestion and that the transmission rate is not lowered when it is determined that it is not caused by congestion, and transmission preset in the user terminal 30 And a transmission unit 60 that transmits data according to the rate.

  The network information described above includes the transmission time of each packet, the data size of the transmission data, the transmission time of the acknowledgment packet from the user terminal 30 (time when the acknowledgment packet is returned), the time when the acknowledgment packet is received, the confirmation response The data size of the packet, the usable bandwidth of the network 20, the transmission throughput, and the like are included, and the delay measurement processing unit 40 acquires and stores the necessary information in the above measurement.

The acknowledgment packet here refers to a so-called ACK (acknowledgment) packet, and is simply referred to as an acknowledgment in the following.
The delay stored in the delay measurement processing unit 40, the statistical value obtained by performing statistical processing on the delay, and the network information are referred to as delay data.

  The delay measurement processing unit 40 measures a delay required for packet transmission / reception in the network 20 when the data transmission device 11 receives an acknowledgment of data (data packet) transmitted to the user terminal 30 or at certain time intervals. Configured to retrieve data.

  The delay here includes, for example, RTT (Round Trip Time) and round trip delay of communication between the user terminal 30 and the data transmission device 11, and a unidirectional delay from the data transmission device 11 to the user terminal 30. Can be adopted.

  In addition, as a delay measurement method by the delay measurement processing unit 40, an estimated value is obtained by a known method such as a method of measuring network information using transmission data or a method of transmitting and measuring a search packet separately from transmission data. A method of deriving may be adopted. However, not only the measurement method but also other measurement methods may be employed.

  The transmission operation control unit 51 estimates (estimates) the queue amount indicating the amount of packets staying in the network 20 at the time of measurement based on the delay measured by the delay measurement processing unit 40, etc. 51A And a congestion detection unit 51B that detects (determines) the degree of congestion of the network 20 by comparing the queue amount estimated by the queue amount estimation unit 51A with a preset threshold (threshold for controlling the transmission unit). Transmission rate control means 51C for controlling the transmission rate of data to be transmitted to the user terminal 30 according to the degree of congestion detected by the congestion detection means 51B, and delay and network information stored in the delay measurement processing section 40 By detecting the increase in delay and making a determination on the cause of the increase in delay, the threshold value and the like are compensated based on the determination result. Has a reference value correcting means 51D, the for execution.

  The queue amount estimation unit 51A is set by the delay measured by the delay measurement processing unit 40 or the transmission rate control unit 51C when the delay measurement processing unit 40 measures the delay or at predetermined time intervals. The queue amount indicating the amount of packets staying in the network 20 is estimated based on the transmission rate or the like. Here, when the queue amount is estimated at the predetermined time, the queue amount estimation unit 51A employs a configuration in which the delay measured by the delay measurement processing unit 40 immediately before the estimation process is used.

  In the first embodiment, the queue amount estimation means 51A estimates the queue amount. In the first embodiment, the delay (d) measured by the delay measurement processing unit 40 and the minimum delay value (d_min) during a fixed time or the same transmission session. And the actual transmission throughput (bw) of the data, and a method of calculating the queue amount (q) by the following formula 1.

    (Equation 1) q = bw × (d−d_min) (1)

  Further, the estimation method is not limited to the above-described equation 1, and for example, the estimation method using the current transmission rate (cw) set by the transmission rate control unit 51C instead of the transmission throughput (bw), -An estimation method using delay (d) instead of d_min) may be adopted.

  The congestion detection unit 51B uses the queue amount estimated by the queue amount estimation unit 51A to estimate the degree of congestion in the network 20 when the queue amount estimation unit 51A estimates the queue amount or at predetermined time intervals. It is configured to detect. Here, when detecting the degree of congestion at every predetermined time, the congestion detection unit 51B employs a configuration in which the queue amount estimated by the queue amount estimation unit 51A immediately before the detection process is used.

  In the first embodiment, as the congestion detection method by the congestion detection unit 51B, the congestion state is obtained when the queue amount (q) estimated by the queue amount estimation unit 51A exceeds a preset threshold value (th). The method of detecting that it is in

  In addition, a method in which a plurality of threshold values are set in advance, and a congestion level is detected depending on which threshold the queue amount (q) estimated in real time belongs to (a method of detecting the degree of congestion in stages) ) May be adopted. Alternatively, a method of calculating and detecting the degree of congestion (cn) by “cn = f (q)” as a function of the queue amount (q) estimated in real time may be employed.

  The transmission rate control means 51C indicates the transmission rate (transmission speed) of data transmitted to the user terminal 30 when the congestion detection means 51B detects the degree of congestion or every predetermined time set in advance. It is configured to control based on the degree of congestion detected by 51B. Here, when the transmission rate is controlled at regular intervals, the transmission rate control unit 51C employs a configuration in which the degree of congestion detected by the congestion detection unit 51B immediately before the transmission rate control is used.

  In the first embodiment, the transmission rate control means 51C reduces the transmission rate (cw) by a predetermined numerical value when the congestion detection means 51B detects that it is in a congestion state. A method of increasing the transmission rate (cw) by a predetermined numerical value when the congestion detection unit 51B detects that the congestion state is not present is adopted.

  In addition, a method in which control is performed such that the transmission rate (cw) is not changed depending on the congestion stage may be adopted as the control method. That is, as described above, when the congestion detection unit 51B detects congestion in stages based on a plurality of preset thresholds, the amount of change in the transmission rate (cw) is changed for each congestion stage. You may take a method.

  Of course, control is performed to reduce the transmission rate (cw) only when the congestion detection means 51B detects that it is in a congestion state, and does not change the transmission rate (cw) when it is detected that the congestion detection means 51B is not in a congestion state. May be adopted.

  In addition, a control method using a predetermined ratio may be adopted instead of the predetermined numerical value used when the transmission rate (cw) is increased or decreased in the control method. Further, for example, a new transmission rate (cw) is calculated based on the current transmission rate (cw), the actual transmission throughput (bw) of data, and the degree of congestion (cn) detected by the congestion detection means 51B. You may take a method.

  The reference value correction processing unit 51D obtains a variation pattern of delay by analyzing the delay data stored and processed by the delay measurement processing unit 40 when the delay measurement processing unit 40 measures the delay or at regular time intervals. It is configured. Further, the reference value correction processing means 51D detects an increase in delay by comparing the delay variation pattern with a predetermined delay variation pattern and determines whether the delay increase has occurred (the delay increase is congested). Or whether it is due to another reason such as a bit error in the network 20).

  In the determination processing by the reference value correction processing unit 51D, when a phenomenon in which the packet arrival interval to the user terminal 30 is extremely short can be observed or analogized, the delay increase is caused by a reason other than the congestion of the network 20. The method of determining the effect (that the delay has increased due to reasons other than congestion) is employed. That is, in the first embodiment, a phenomenon in which the arrival interval of packets to the user terminal 30 is extremely short is adopted as the delay variation pattern specified in advance.

  Specifically, for example, when the transmission time of each packet is compared with the delay of the packet, the delay of the packet decreases almost linearly (after a sharp increase) with respect to the increase of the transmission time of each packet. Pattern (phenomenon) that the user terminal 30 returns a confirmation response, a pattern in which the time interval at which the user terminal 30 returns a confirmation response is very small, and “time interval at which the data transmission device 11 receives the confirmation response from the user terminal 30” A pattern in which the data size of the response is smaller than the value obtained by dividing the actual transmission throughput (bw) of the data by “the interval between transmission times of the confirmation response” is “the data size of the transmission data is divided by the available bandwidth of the network 20 The pattern that is smaller than “value” or “interval of the time when the acknowledgment is received” is “the data size of the transmission data is the available band of the network 20 Reference value correcting means 51D if it could get a pattern, that is smaller than the value obtained by dividing "a, adopts a configuration in which a delay for reasons other than congestion determined that increased.

  When it is determined that the delay has increased due to a cause other than congestion, the reference value correction processing unit 51D temporarily corrects a parameter (congestion parameter) that affects the detection of the degree of congestion performed by the congestion detection unit 51B. It is configured. The congestion parameter includes a delay measured by the delay measurement processing unit 40, a threshold used when the congestion detection unit 51B detects the degree of congestion (a threshold for controlling the transmission unit 60), and a degree of congestion (cn). Point to.

  In the first embodiment, the threshold value (th) used by the congestion detection unit 51B is increased (temporarily) for a certain period of time as the correction method by the reference value correction processing unit 51D.

  In addition, for example, a method of reducing the degree of congestion (cn) used by the congestion detection means 51B for a certain time, a method for reducing the delay (d) measured by the delay measurement processing unit 40 for a certain time, or Instead of the delay (d) newly measured by the delay measurement processing unit 40, a method of temporarily using a past delay (d) stored and processed immediately before may be adopted as the correction method.

  Further, not only one of the correction for temporarily reducing the delay (d) measured by the delay measurement processing unit 40 and the correction for temporarily increasing the threshold used for detecting the degree of congestion, but also a correction method in which both are combined. May be adopted.

  Each of the above corrections is intended to control the transmission rate of data transmitted to the user terminal 30 so as not to decrease. Therefore, in the first embodiment, each correction is performed so that such control can be realized. The correction value is set in advance.

  As described above, either or both of the delay measured by the delay measurement processing unit 40 by the reference value correction processing unit 51D and the threshold used for detecting the degree of congestion (threshold for controlling the transmission unit 60) are corrected. Thus, the congestion detection unit 51B can execute the above detection process using the adjusted congestion parameter, and therefore, it is possible to suppress erroneous detection of congestion by the congestion detection unit 51B. It is possible to prevent excessive transmission rate lowering control by the transmission rate control means 51C.

  The data transmission device 11 acquires a data request message from the user terminal 30 via the intervening network 20, and according to this, the data related to the request is transmitted at the transmission rate set by the transmission rate control means 51C. A configuration of transmitting to the user terminal 30 is adopted.

  Here, when the origin server is adopted as the data transmission device 11, since all the original data is held by itself, the data can be transmitted at the set transmission rate.

  Further, when a relay server device or a data communication device is adopted as the data transmission device 11, the original data is copied in advance as a cache in its own storage area, or the data stream transmitted from the origin server is temporarily stored. By storing it in its own storage area used as a buffer, it does not depend on the throughput of the network between the origin server and the data transmission device 11 (the amount of data that can be processed within a certain time), and at a set transmission rate. Data can be transmitted.

  Furthermore, as a method for acquiring a data request message from the user terminal 30 when a relay server device or a data communication device is employed as the data transmission device 11, for example, the request message transmitted from the user terminal 30 to the origin server A router or the like installed in the route from the terminal 30 to the origin server and connected to the data transmission device 11 transfers the data to the data transmission device 11 instead of the origin server based on conditions such as header information of the request message. This method can be adopted.

  Further, not limited to the acquisition method described above, for example, a method in which the user terminal 30 explicitly designates the data transmission device 11 as a proxy (proxy server) and transmits a data request message may be employed. In addition, when the user terminal 30 performs address resolution of a destination by using a DNS (Domain Name System) or the like in order to transmit a data request message to the origin server, the DNS or the like of the data transmission device 11 instead of the origin server. You may make it employ | adopt the method of returning an address.

(Description of operation)
Next, the operation of the data transmission apparatus 11 shown in FIG. 1 will be described based on the flowcharts shown in FIGS. First, with reference to FIG.1 and FIG.2, the operation | movement content from the network delay measurement process by the data transmitter 11 to the rate control of data transmission is demonstrated.

  When the data transmission device 11 receives an acknowledgment of the data (data packet) transmitted to the user terminal 30, the delay measurement processing unit 40 measures the delay required for packet transmission / reception in the network 20 and stores the acquired delay data. Storage processing is performed in a memory or the like (not shown) (FIG. 2: S201).

  Next, when the delay measurement processing unit 40 measures the delay, the queue amount estimation unit 51A uses the delay measured by the delay measurement processing unit 40, the transmission rate set by the transmission rate control unit 51C, and the like. The queue amount indicating the packet amount staying in the network 20 is estimated. In the first embodiment, the queue amount estimation means 51A estimates the queue amount based on the above equation 1 (FIG. 2: S202).

  Subsequently, when the queue amount estimation unit 51A estimates the queue amount, the congestion detection unit 51B detects the degree of congestion in the network 20 based on the estimated queue amount (FIG. 2: S203). .

  In the first embodiment, the congestion detection unit 51B detects that a congestion state exists when the queue amount estimated in real time exceeds a preset threshold. On the other hand, when the queue amount estimated in real time does not exceed a preset threshold value, the congestion detection unit 51B detects that there is no congestion state (FIG. 2: S203).

  When the congestion detection unit 51B detects the degree of congestion, the transmission rate control unit 51C uses the transmission rate of data transmitted to the user terminal 30 based on the degree of congestion detected by the congestion detection unit 51B ( (Transmission speed) is controlled (FIG. 2: S204).

  In the first embodiment, the transmission rate control unit 51C reduces the transmission rate by a preset numerical value when the congestion detection unit 51B detects that it is in a congestion state. On the other hand, when the congestion detection unit 51B detects that the congestion state is not present, the transmission rate control unit 51C increases the transmission rate by a preset numerical value (FIG. 2: S204).

  Next, with reference to FIG. 1 and FIG. 3, operations from the network delay measurement process to the determination regarding the cause of the increase in delay and the correction of the congestion parameter (congestion level detection standard) associated therewith will be described.

  First, when the data transmission device 11 receives an acknowledgment of data (data packet) transmitted to the user terminal 30, the delay measurement processing unit 40 measures the delay related to packet transmission in the network 20 and acquires the delayed data. Is stored in an internal memory or the like (not shown) (FIG. 3: S301).

  Next, when the delay measurement processing unit 40 measures the delay, the reference value correction processing unit 51D, based on the delay variation pattern obtained by analyzing the delay data stored and processed in the delay measurement processing unit 40, A determination is made regarding the cause of the increase in delay. Specifically, when a pattern equivalent to the variation pattern specified in advance for the delay is obtained, the reference value correction processing unit 51D determines that the delay has increased due to a cause other than congestion (FIG. 3: S302).

  Subsequently, the reference value correction processing unit 51D that determines that the delay has increased due to a cause other than congestion (FIG. 3: S302 / Yes), the delay measured by the delay measurement processing unit 40 or the congestion detection unit 51B indicates the degree of congestion. The threshold used for detection is corrected (FIG. 3: S303). Then, a determination process related to the subsequent data packet is executed.

  On the other hand, the reference value correction processing means 51D that has determined that the increase in delay is due to congestion of the network 20 (that delay has increased due to congestion) (FIG. 3: S302 / No), corrects the threshold value. Instead, the determination process related to the subsequent data packet is executed.

Here, the delay measurement processing (FIG. 2: S201) by the delay measurement processing unit 40 described above may be performed at predetermined time intervals.
Similarly, the queue amount estimation process (FIG. 2: S202) by the queue amount estimation unit 51A may be performed at predetermined time intervals. In this case, the queue amount estimation unit 51A uses the delay measured and stored by the delay measurement processing unit 40 immediately before the estimation process.
Similarly, the detection of the degree of congestion by the congestion detection means 51B (FIG. 2: S203) may be performed at predetermined time intervals. In this case, the congestion detection unit 51B uses the queue amount obtained by the queue amount estimation unit 51A in the estimation process immediately before the authorization.
Similarly, the transmission rate control by the transmission rate control means 51C (FIG. 2: S204) may be performed at predetermined time intervals. In this case, the transmission rate control means 51C uses information relating to the degree of congestion detected immediately before the congestion detection means 51B controls the transmission rate.

The delay measurement processing by the delay measurement processing unit 40 (FIG. 3: S301) may be performed at predetermined time intervals.
Similarly, the determination regarding the cause of the increase in delay by the reference value correction processing means 51D (FIG. 3: S302) may be performed at predetermined time intervals. In this case, the reference value correction processing unit 51D uses the delay data obtained by the measurement process performed immediately before the determination by the delay measurement processing unit 40.

  Further, the execution contents of each step in the above steps S201 to S204 (FIG. 2) and S301 to S303 (FIG. 3) may be programmed, and this series of control programs may be realized by a computer. .

(Effect of 1st Embodiment)
In the data transmission device 11 according to the first embodiment, as described above, the threshold value that the congestion detection unit 51B refers to when detecting the degree of congestion of the network 20 is delayed due to reasons other than congestion. Since the reference value correction processing unit 51D determined to have increased is temporarily corrected, it prevents the transmission rate control unit 51C from unnecessarily lowering the transmission rate in the case of an increase in delay not caused by congestion. This makes it possible to improve the throughput.

  That is, according to the data transmitting apparatus 11, since significant traffic control can be realized, it is possible to prevent erroneous detection of congestion, thereby improving transmission efficiency.

(Second Embodiment)
Next, a data transmission apparatus according to a second embodiment of the present invention will be described with reference to FIGS. Here, the same reference numerals are used for the same constituent members as those of the first embodiment described above.

(Overall configuration)
Here, differences from the configuration according to the first embodiment will be described with reference to FIG.

  In the second embodiment, the network 20 includes a base station 20 </ b> A that measures a radio wave intensity such as a radio wave intensity or a bit error in a wireless part of the network 20 or receives a radio wave from the user terminal 30. That is, the base station 20A is a data communication device that configures the network 20, such as eNodeB (LTE radio base station).

  The data transmission device 12 that performs data transmission processing in response to a request from the user terminal 30 includes each component (FIG. 2: delay measurement processing unit 40, queue amount estimation) of the data transmission device 11 according to the first embodiment described above. In addition to the means 51A, the congestion detection means 51B, the transmission rate control means 51C, and the transmission unit 60), the index value (index) of the radio wave condition applied to the wireless part of the network 20 from the user terminal 30 or the base station 20A at regular intervals. A radio wave state acquisition processing unit 70 for acquisition is provided. Further, the data transmitting apparatus 12 has a configuration in which a transmission operation control unit 52 having a reference value correction processing unit 52D including the same function is used instead of the reference value correction processing unit 51D (FIG. 2). .

  That is, in addition to the functional configuration of the reference value correction processing unit 51D (FIG. 2) according to the first embodiment described above, the reference value correction processing unit 52D determines whether the cause of the increase in delay is a radio wave state acquisition processing unit. 70 has a characteristic functional configuration that is executed based on the radio wave condition index value acquired and stored in an internal memory or the like (not shown).

  Here, in the second embodiment, the radio wave state acquisition processing unit 70 is configured to acquire an index of SINR (Signal to Interference plus Noise Ratio) measured by the user terminal 30 as the radio wave state index value. ing. This SINR is an index representing the ratio of signal strength to noise and interference. The larger the value, the higher the signal strength and the less likely a bit error occurs.

  In addition, the radio wave condition acquisition processing unit 70 is not limited to the SINR index, but acquires a radio wave condition index such as CQI (Channel Quality Indicator), RSSI (Received Signal Strength Indicator), or ASU (Arbitrary Strength Unit). It may be configured.

The CQI is an index proportional to SINR and represents the quality of the radio channel. A larger CQI value indicates a better quality (fewer errors).
The RSSI or ASU is an index representing the strength of the signal received on the user terminal 30 side, and is an index reflected on the number of antennas of the mobile phone. Both of these values are characterized in that the larger the value, the higher the reception sensitivity (the error is less likely to occur).

  Each of the above-described indexes represents the strength and quality of the signal, and has a correlation that an error is less likely to occur as these values increase. The radio wave state acquisition processing unit 70 may be configured to acquire an index that an error is less likely to occur as the value is smaller.

Further, the reference value correction processing unit 52D is configured to execute the determination related to the cause of the increase in delay when the radio wave state acquisition processing unit 70 acquires the radio wave state index value or at predetermined time intervals. Has been.
Here, when the determination is performed at the predetermined time, the reference value correction processing unit 52D employs a configuration in which the radio wave state acquisition processing unit 70 uses the radio wave state index value acquired immediately before the determination. .

  Here, as a determination method related to the cause of the increase in delay performed by the reference value correction processing means 52D based on the radio wave condition index value, for example, the radio wave condition index value exceeds a predetermined set value (threshold). In such a case, it is possible to adopt a method of determining that the delay has increased due to a cause other than the congestion when it falls or falls. In the second embodiment, when the radio wave condition index value acquired by the radio wave condition acquisition processing unit 70 falls below a predetermined set value, the reference value correction processing means 52D increases the delay due to reasons other than congestion. The configuration of judging the effect was adopted.

  In addition, the use of the radio wave state index value acquired by the radio wave state acquisition processing unit 70 is not limited to the above-described determination method, and for example, in combination with the correction method described above, the radio wave state with respect to the delay measured by the delay measurement processing unit 40 A method of correcting by adding (proportional) a value corresponding to the index value of the signal or a threshold value (threshold value for controlling the transmission unit 60) referred to when the congestion detection unit 51B estimates the degree of congestion A method of correcting by adding a value according to the value can be employed.

  That is, the reference value correction processing unit 52D that determines that the delay has increased due to a cause other than congestion temporarily corrects a parameter (congestion parameter) that affects the detection of the degree of congestion performed by the congestion detection unit 51B. It is configured.

Here, it supplements about "the method of adding and correct | amending the value according to an index value" mentioned above.
In the second embodiment, an error is more likely to occur as the index value is smaller. Therefore, retransmission and error repair by HARQ are more likely to occur, and thus there is a high possibility that an increase in delay not caused by congestion will occur.

  Therefore, if the delay measured by the delay measurement processing unit 40 is d, the corrected delay is d ′, and the index value acquired by the radio wave state acquisition processing unit 70 is x, the reference value correction processing unit 52D For example, a method of “correcting so that the delay (d) is decreased as the index value (x) is smaller” may be employed using the method shown in the following Expression 2 or 3.

    (Equation 2) d ′ = da− (b−x) (2)

    (Expression 3) d ′ = d × (x−b) / a (3)

  Further, when the threshold value to be referred to when the congestion detection unit 51B detects the degree of congestion is set to th and the corrected threshold value is set to th ′, the reference value correction processing unit 52D is supplied with a method represented by, for example, the following formula 4 or formula 5. May be used to “correct so that the threshold value (th) increases as the index value (x) decreases”.

    (Equation 4) th ′ = th + a × (b−x) (4)

    (Expression 5) th ′ = th × (b−x) / a (5)

  Here, a and b in the above formulas 1 to 4 are set values that can take either positive or negative values, and are set in advance before the execution of the correction processing by the reference value correction processing means 52D.

  In addition to the configuration described above, the reference value correction processing unit 52D is configured to “correct so that the delay (d) decreases as the index value (x) increases”, or “the index value (x) is large. A configuration of “correcting so as to increase the threshold (th) as much as possible” may be employed.

(Description of operation)
Next, the operation content of the data transmission device 12 shown in FIG. 5 will be described.
Here, with respect to the operation contents from the network delay measurement processing to the data transmission rate control by the data transmission apparatus 12, the operation contents of the data transmission apparatus 11 (FIG. 1) described in accordance with FIG. 2 in the first embodiment. (FIG. 2: S201 to S204).

  Therefore, the operation contents from the network delay measurement process by the data transmission device 12 to the determination of the cause of the increase in delay and the correction of the congestion parameter associated therewith will be described based on the flowchart shown in FIG.

  The radio wave state acquisition processing unit 70 acquires an index value of the radio wave state in the network 20 from the user terminal 30 or the base station 20A at regular intervals and stores it in an internal memory or the like (not shown) (FIG. 5: S501).

  When the radio wave state acquisition processing unit 70 acquires the radio wave state index value or at predetermined time intervals, the reference value correction processing unit 52D uses the radio wave state index value acquired by the radio wave state acquisition processing unit 70 in advance. The determination regarding the cause of the increase in delay is executed by comparing with the determined set value (FIG. 5: S502).

  That is, the reference value correction processing means 52D that has determined that the delay has increased due to a cause other than congestion of the network 20 (FIG. 5: S502 / Yes), the delay measured by the delay measurement processing section 40 or the congestion detection means 51B The threshold value used when estimating the degree is temporarily corrected (FIG. 5: S503). Then, a determination process related to the subsequent data packet is executed.

  On the other hand, the reference value correction processing unit 52D that has determined that the delay has increased due to the congestion of the network 20 (FIG. 5: S502 / No) is a determination regarding the subsequent data packet without correcting the threshold value or the like. Execute the process.

  Further, the execution contents of each step in the above steps S501 to S503 (FIG. 5) may be programmed, and the series of control programs may be realized by a computer.

(Effect of 2nd Embodiment)
In the data transmission device 12 according to the second embodiment, the reference value correction processing unit 52D that performs the determination regarding the cause of the increase in delay based on the fluctuation pattern of the delay of the network and the radio wave state in the wireless part is caused by the congestion. A configuration is adopted in which the congestion parameter used by the congestion detection means 51B is significantly corrected when it is determined that the delay is not increased.
Therefore, when an increase in delay due to reasons other than congestion occurs, the detection processing based on the adjusted congestion parameter can be executed by the congestion detection means 51B, so that the transmission rate control means 51C transmits unnecessarily. The inconvenience of lowering the rate can be suppressed, thereby improving the throughput.

  That is, in the data transmission device 12, the radio wave state acquisition processing unit 70 that acquires the radio wave state index value for the wireless portion of the network 20 from the user terminal 30 or the base station 20A at regular intervals functions effectively, and significant traffic is received. Since control can be realized, it is possible to prevent erroneous detection of congestion, thereby improving transmission efficiency.

  The embodiment described above is a preferable specific example in the data transmission apparatus, the data transmission method, and the program thereof, and may have various technically preferable limitations. However, the technical scope of the present invention is not limited to these embodiments unless specifically described to limit the present invention.

  The following summarizes the main points of the new technical contents of the above-described embodiment, but the present invention is not necessarily limited to this.

(Appendix 1)
A data transmission device including a transmission unit for transmitting data to a user terminal,
A determination function that determines whether or not the increase in delay in data transmission is due to network congestion based on a predetermined criterion, and this determination function transmits when it is determined that the increase is not due to congestion A data transmission device comprising: a transmission operation control unit having a transmission rate control function for controlling an operation of the transmission unit so as not to decrease a rate.

(Appendix 2)
In the data transmission device according to the appendix 1,
The transmission operation control unit determines that it is not caused by congestion when a delay in the data transmission indicates a phenomenon in which the delay time increases sharply and then decreases in a line shape with respect to an increase in the transmission time of each packet. A data transmitting apparatus characterized by:

(Appendix 3)
In the data transmission device according to the appendix 1,
The transmission operation control unit obtains a transmission time of an acknowledgment from the user terminal for transmission data, and an interval of the transmission time is smaller than a value obtained by dividing the data size of the transmission data by the available bandwidth of the network A data transmission device characterized by determining that it is not caused by congestion.

(Appendix 4)
In the data transmission device according to the appendix 1,
The transmission operation control unit is not caused by congestion when an interval of time when an acknowledgment for transmission data is received from the user terminal is smaller than a value obtained by dividing the data size of the transmission data by the available bandwidth of the network. A data transmission device characterized by determining.

(Appendix 5)
In the data transmission device according to the appendix 1,
When the transmission operation control unit obtains a variation pattern in which the time interval at which the confirmation response to the transmission data is received from the user terminal is smaller than the value obtained by dividing the data size of the confirmation response by the throughput of the data transmission. A data transmitting apparatus characterized by determining that the error is not caused by congestion.

(Appendix 6)
In the data transmission device according to the appendix 1,
Furthermore, a radio wave state acquisition processing unit that acquires a radio wave state index value in the wireless part of the network,
The data transmission apparatus according to claim 1, wherein the transmission operation control unit performs the determination based on a magnitude relationship between the radio wave condition index value and a predetermined set value.

(Appendix 7)
In the data transmission device according to the appendix 1,
Furthermore, a radio wave state acquisition processing unit that acquires a radio wave state index value in the wireless part of the network,
The data transmission apparatus according to claim 1, wherein the transmission operation control unit determines that it is not caused by congestion when an index value of the radio wave state falls below a predetermined set value.

(Appendix 8)
In the data transmission device according to the appendix 1,
Furthermore, a radio wave state acquisition processing unit that acquires a radio wave state index value in the wireless part of the network,
The data transmission apparatus according to claim 1, wherein the transmission operation control unit determines that it is not caused by congestion when an index value of the radio wave condition exceeds a predetermined set value.

(Appendix 9)
In the data transmission device according to the appendix 1,
Furthermore, a radio wave state acquisition processing unit that acquires a radio wave state index value in the wireless part of the network,
The data transmission apparatus according to claim 1, wherein the transmission operation control unit determines that the signal is not caused by congestion when the radio wave condition index value is not within a predetermined setting range.

(Appendix 10)
In the data transmission device according to any one of the supplementary notes 1 to 9,
The transmission operation control unit controls the operation of the transmission unit by performing correction that temporarily raises a threshold for control of the transmission unit when it is determined that the transmission operation control unit is not caused by congestion. apparatus.

(Appendix 11)
In the data transmission device according to any one of the supplementary notes 1 to 9,
In addition, a delay measurement processing unit that measures the delay for the data transmission,
The transmission operation control unit controls the operation of the transmission unit by performing correction to temporarily reduce the delay measured by the delay measurement processing unit when it is determined that the transmission operation control unit is not caused by congestion. Data transmission device.

(Appendix 12)
In the data transmission device according to appendix 10,
In addition, a delay measurement processing unit that measures the delay for the data transmission,
The transmission operation control unit controls the operation of the transmission unit by performing correction to temporarily reduce the delay measured by the delay measurement processing unit together with the correction when it is determined that the transmission operation control unit is not caused by congestion. A data transmission device characterized by the above.

(Appendix 13)
In the data transmission device according to any one of the supplementary notes 6 to 9,
The transmission operation control unit controls the operation of the transmission unit by performing correction by adding a value corresponding to (in proportion to) the index value of the radio wave state to a threshold value for controlling the transmission unit. Transmitter device.

(Appendix 14)
In the data transmission device according to any one of the supplementary notes 6 to 9,
In addition, a delay measurement processing unit that measures the delay for the data transmission,
The transmission operation control unit controls the operation of the transmission unit by performing correction for subtracting a value corresponding to (in proportion to) the index value of the radio wave state from the delay measured by the delay measurement processing unit. Characteristic data transmission device.

(Appendix 15)
In the data transmission device according to any one of the supplementary notes 6 to 9,
In addition, a delay measurement processing unit that measures the delay for the data transmission,
The transmission operation control unit is configured to add a value corresponding to (in proportion to) the index value of the radio wave state to a threshold for control of the transmission unit, or from the delay measured by the delay measurement processing unit, the radio wave state index A data transmitting apparatus, wherein the operation of the transmitting unit is controlled by performing correction for subtracting a value corresponding to (proportional to) the value.

(Appendix 16)
In the data transmission device according to any one of the supplementary notes 6 to 9,
In addition, a delay measurement processing unit that measures the delay for the data transmission,
The transmission operation control unit includes a correction for adding (proportional) a value corresponding to (in proportion to) the index value of the radio wave state to a threshold for control of the transmission unit, and the radio wave state index from the delay measured by the delay measurement processing unit. A data transmitting apparatus, wherein the operation of the transmitting unit is controlled by performing correction for subtracting a value corresponding to (proportional to) the value.

(Appendix 17)
In a data transmission device including a transmission unit for transmitting data to a user terminal,
Determine whether or not the increase in delay for data transmission is due to network congestion based on pre-set criteria,
Here, when it is determined that it is not caused by congestion, a preset detection criterion is corrected,
Based on this corrected detection criteria, detect the degree of congestion,
A data transmission method characterized in that the operation of the transmission unit is controlled so as not to lower the transmission rate in accordance with the detection result.

(Appendix 18)
In a data transmission device including a transmission unit for transmitting data to a user terminal,
A delay cause determination function for determining whether or not an increase in delay for data transmission is due to network congestion based on a predetermined criterion;
A detection standard correction function that corrects a preset detection standard when it is determined that the delay cause determination function is not caused by congestion,
A congestion detection function that detects the degree of congestion based on the detection standard corrected by this detection standard correction function,
A data transmission program for causing a computer to realize a transmission rate control function for controlling the operation of the transmission unit so as not to lower the transmission rate according to the detection result by the congestion detection function.

  This application claims the priority on the basis of Japanese application Japanese Patent Application No. 2012-276440 for which it applied on December 19, 2012, and takes in those the indications of all here.

  The present invention can be applied to an estimation device that estimates a network situation such as the amount of queues (amount of staying packets), available bandwidth, or bit error rate that is staying in the network from a delay. Further, the present invention can be applied to a transmission rate control apparatus that controls a transmission rate by simulating behavior equivalent to TCP in a protocol different from TCP such as UDP.

11, 12 Data transmission device 20 Network 20A Base station 30 User terminal 40 Delay measurement processing unit 51, 52 Transmission operation control unit 51A Queue amount estimation unit 51B Congestion detection unit 51C Transmission rate control unit 51D, 52D Reference value correction processing unit 60 Transmission 70 Radio wave condition acquisition processing unit

Claims (12)

A data transmission device including a transmission unit for transmitting data to a user terminal,
A determination function that determines whether or not the increase in delay in data transmission is due to network congestion based on a predetermined criterion, and this determination function transmits when it is determined that the increase is not due to congestion a transmission rate control function for controlling the operation of the transmission unit so as not to lower the rate, the transmission operation control unit having,
A delay measurement processing unit that measures a delay required for the data transmission ,
The transmission operation control unit controls the operation of the transmission unit by performing correction to temporarily reduce the delay measured by the delay measurement processing unit when it is determined that the transmission operation control unit is not caused by congestion. Data transmission device. The data transmission device according to claim 1, wherein
The transmission operation control unit determines that it is not caused by congestion when a delay in the data transmission indicates a phenomenon in which the delay time increases sharply and then decreases in a line shape with respect to an increase in the transmission time of each packet. A data transmitting apparatus characterized by: The data transmission device according to claim 1, wherein
The transmission operation control unit obtains a transmission time of an acknowledgment from the user terminal for transmission data, and an interval of the transmission time is smaller than a value obtained by dividing the data size of the transmission data by the available bandwidth of the network A data transmission device characterized by determining that it is not caused by congestion. The data transmission device according to claim 1, wherein
The transmission operation control unit is not caused by congestion when an interval of time when an acknowledgment for transmission data is received from the user terminal is smaller than a value obtained by dividing the data size of the transmission data by the available bandwidth of the network. A data transmission device characterized by determining. The data transmission device according to claim 1, wherein
Furthermore, a radio wave state acquisition processing unit that acquires a radio wave state index value in the wireless part of the network,
The data transmission apparatus according to claim 1, wherein the transmission operation control unit performs the determination based on a magnitude relationship between the radio wave condition index value and a predetermined set value. The data transmission device according to claim 1, wherein
When the transmission operation control unit obtains a variation pattern in which the time interval at which the confirmation response to the transmission data is received from the user terminal is smaller than the value obtained by dividing the data size of the confirmation response by the throughput of the data transmission. A data transmitting apparatus characterized by determining that the error is not caused by congestion. The data transmission device according to claim 1, wherein
Further, radio wave condition acquisition for acquiring an index value of the radio wave condition in the wireless part of the network
With a processing unit,
The transmission operation control unit is configured such that the radio wave condition index value falls within a predetermined setting range.
A data transmitting apparatus characterized by determining that it is not caused by congestion when there is not. In the data transmission device according to any one of claims 1 to 7,
The transmission operation control unit controls the operation of the transmission unit by performing correction that temporarily raises a threshold for control of the transmission unit together with the correction when it is determined that the transmission operation control unit is not caused by congestion. Data transmission device. The data transmission apparatus according to claim 5, wherein
Before Symbol transmission operation control unit, depending from the delay measured by the addition of a value corresponding to the index value of the radio wave state to the threshold according to the control of the transmission portion correction or the delay measurement processing section to the index value of the radio wave state A data transmitting apparatus, wherein the operation of the transmitting unit is controlled by performing correction for subtracting the obtained value. The data transmission apparatus according to claim 5, wherein
The transmission operation control unit is configured to add a value corresponding to (in proportion to) the index value of the radio wave state to a threshold for control of the transmission unit, or from the delay measured by the delay measurement processing unit, the radio wave state index A data transmitting apparatus, wherein the operation of the transmitting unit is controlled by performing correction for subtracting a value corresponding to (proportional to) the value. In a data transmission device including a transmission unit for transmitting data to a user terminal,
Measure the delay in data transmission,
The increase of such delay for data transmission is determined based on the previously provided criteria whether or not due to network congestion,
Here, when it is determined that it is not caused by congestion, a preset detection criterion is corrected,
Based on this corrected detection criteria, detect the degree of congestion,
Control the operation of the transmitter so as not to decrease the transmission rate according to the result of this detection ,
A data transmission method characterized in that, when it is determined that it is not caused by the congestion, a correction for temporarily reducing the measured delay in data transmission is performed . In a data transmission device including a transmission unit for transmitting data to a user terminal,
A function to measure the delay in data transmission,
A delay cause determination function for determining whether or not the increase in delay for data transmission is due to network congestion based on a predetermined criterion;
A detection standard correction function that corrects a preset detection standard when it is determined that the delay cause determination function is not caused by congestion,
A congestion detection function that detects the degree of congestion based on the detection standard corrected by this detection standard correction function,
A transmission rate control function for controlling the operation of the transmission unit so as not to lower the transmission rate according to the detection result by the congestion detection function,
A data transmission program for causing a computer to realize a correction function for temporarily reducing a delay in data transmission when it is determined that the congestion is not caused .

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